Improvement in processes of producing enlarged pictures upon fabrics



UNITED STATES WILHELM WINTER, OF PRAGUE, AUSTRIA.

IMPROVEMENT IN PROCESSES 0F PRODUCING ENLARGED PICTURES UPON FABRIQS.

Specification forming part of Letters Patent No. 196,510, dated October23, 1877; application filed April 19, 1877.

To all whom it may concern Be it known that I, 'WILHELM WINTER, of

Prague, in the Empire of Austria, have invented a certain new and usefulImprovement in Photography, ofwhich the following is a specification Theobject of this invention is to produce magnified positive photographs onwoven fabrics, such as linen, cotton, silk, or wool, and with the use ofiodide or bromide of silver.

The process consists, essentially, in impregnating the woven fabric withiodide or bro mide of 'silver, and thereby making it so sensitive tolight that from a negative plate of about eight square inches amagnified positive photograph of up to more than forty square feet maybe produced on the said woven fabric. When electric light is employedthe positive photograph maybe produced in from one to four minutes.

The iodides and bromides are in general use for producing negatives, buthardly at all for positives; and, although manyattempts have been madeto utilize the sensibility of these salts for the purpose of rapidlyproducing magnified photographs on paper, these'experiments have nearlyalways remained futile.

The proportions of the chemicals to be used vary not only according totemperature, but also according to the density and material of the wovenfabric, so that, in the case of lower temperatures and denser wovenfabrics, which do not so easily absorb fluids, the solutions must bemade stronger, and iodides must beused in preference to bromides.

By way of example, there shall now be described the proportions that maybe used at a temperature of from 20 to 23 centigrade, and with linen orcotton fabrics of average density and fineness. This description willserve as a measure for the possible variations under thepreviously-mentioned circumstances.

The woven fabrics must be first freed from all chemical impurities, andthe subsequent operations may then follow, in the manner now to bedescribed.

First, the treatment with bromides: The woven fabric is passed through asolution composed of four (4) parts by weight of bromide of potassium,one (1) part of bromide of cadmium, and two hundred and forty (240)parts of water, soas to be equally wet 011 both sides, and is then hrmgup to dry.

Secondly, the treatment with silver: The dried woven fabric is passedthrough a solution of four (4) parts by weight of nitrate of silver, one(1) part of citric acid, and one 111111- dred and orty (140) parts ofwater, and again dried.

Thirdly, the exposure to light: For this purpose it is generallypreferable to use electric light, which may be produced by adynamoelectric apparatus. In all other respects the proceedings are thesame as in the production of magnified photographs by means of the solarcamera. The sensitized woven fabric is exposed to the light until thepositive photograph is distinctly visible thereon. The timenecessary forthis exposure depends upon the size and strength of the negative.Generally one to four minutes are required.

Fourthly, the development: A solution composed of ten (10) parts ofpyrogallic acid, fortyfive (45 parts of citric acid, and four hundredand ten (416, parts of water is put intoa large flat pan, and the wovenfabric is left in this solution until the photographic picture or printthereon is sufliciently'd eveloped.

The remaining proceedings are as usual in photographic processes. Thepicture is well Washed, then toned and fixed,and finally again wellwashed.

It is evident that, without departing from the substance of thisinvention, other sources of light and other iodides and bromides may beused for producing magnified photographs or prints on woven fabrics.

I claim- 1. In the art of photography, the process of producing positivephotographs directly upon a fabric by preparing said fabric with asolution of bromide or iodide of potassium and bromide or iodide ofcadmium, or their equivalents, substantially as described.

2. In the art of photography, the process of preparing a fabric by firsttreating the same with a solution of bromide or iodide of potassium andbromide or iodide of cadmium, and afterward with a solution of nitrateof silver and citric acid, substantially as described, for the purposespecified. v

3. The process of producing positive photographs directly upon a fabric,consisting in first preparing the fabric with a solution of bromide ofpotassium and bromide of cadmium, or their equivalents, then sensitizingthe fabric by means of a solution of nitrate of silver and citric acid,exposing the fabric so prepared to the electric light for the productionof the positive photograph, and developing such positive photograph bymeans of a solution of pyrogallic acid and citric acid, and

finally toning and finishingin the usual manner, substantially ashereinbefore specified.

In Witness that I claim the foregoing I have hereunto set my hand this13th day of March, 1877.

WILHELM WINTER.

Witnesses G. 0. PAGET, '1. BARHAL.

